Turbomachines are widely utilized in fields such as power generation. For example, a conventional gas turbine system includes a compressor section, a combustor section, and at least one turbine section. The compressor section is configured to compress air as the air flows through the compressor section. The air is then flowed from the compressor section to the combustor section, where it is mixed with fuel and combusted, generating a hot gas flow. The hot gas flow is provided to the turbine section, which utilizes the hot gas flow by extracting energy from it to power the compressor, an electrical generator, and other various loads.
The combustor sections of turbomachines generally include tubes or ducts for flowing the combusted hot gas therethrough to the turbine section or sections. Recently, combustor sections have been introduced which include tubes or ducts that shift the flow of the hot gas. For example, ducts for combustor sections have been introduced that, while flowing the hot gas longitudinally therethrough, additionally shift the flow radially and/or tangentially such that the flow has various angular components. These designs have various advantages, including eliminating first stage nozzles from the turbine sections. The first stage nozzles were previously provided to shift the hot gas flow, and may not be required due to the design of these ducts. The elimination of first stage nozzles may eliminate associated pressure drops and increase the efficiency and power output of the turbomachine.
However, the connection of these ducts to turbine sections is of increased concern. For example, because known ducts do not simply extend along a longitudinal axis, but are rather shifted off-axis from the inlet of the duct to the outlet of the duct, thermal expansion of the ducts can cause undesirable shifts in the ducts along or about various axes. These shifts can cause stresses and strains within the ducts, and may cause the ducts to fail.
Aspects and advantages of the disclosure will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the disclosure.
In one embodiment, a turbomachine is provided. The turbomachine includes a plurality of transition ducts disposed in a generally annular array and including a first transition duct and a second transition duct. Each of the plurality of transition ducts includes an inlet, an outlet, and a passage defining an interior and extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of each of the plurality of transition ducts is offset from the inlet along the longitudinal axis and the tangential axis. The outlet of at least one transition duct of the plurality of transition ducts includes an inner flange and an outer flange. The turbomachine further includes a support ring assembly downstream of the plurality of transition ducts along a hot gas path, a plurality of bore holes defined in the inner flange and outer flange, and a plurality of mating bore holes defined in the support ring assembly. The turbomachine further includes a plurality of mechanical fasteners connecting the inner flange and the outer flange of the at least one transition duct to the support ring assembly, each of the plurality of mechanical fasteners extending through a bore hole and mating bore hole. A first one of the bore holes or mating bore holes has a first maximum radial gap and a first maximum tangential gap relative to the mechanical fastener extending through the first one of the bore holes or mating bore holes. A second one of the bore holes or mating bore holes has a second maximum radial gap and a second maximum tangential gap relative to the mechanical fastener extending through the second one of the bore holes or mating bore holes. The second maximum radial gap is greater than the first maximum radial gap or the second maximum tangential gap is greater than the first maximum tangential gap.
In another embodiment, a turbomachine is provided. The turbomachine includes a plurality of transition ducts disposed in a generally annular array and including a first transition duct and a second transition duct. Each of the plurality of transition ducts includes an inlet, an outlet, and a passage defining an interior and extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of each of the plurality of transition ducts is offset from the inlet along the longitudinal axis and the tangential axis. The outlet of at least one transition duct of the plurality of transition ducts includes an inner flange and an outer flange. The turbomachine further includes a support ring assembly downstream of the plurality of transition ducts along a hot gas path, a plurality of bore holes defined in the inner flange and outer flange, and a plurality of mating bore holes defined in the support ring assembly. The turbomachine further includes a plurality of mechanical fasteners connecting the inner flange and the outer flange of the at least one transition duct to the support ring assembly, each of the plurality of mechanical fasteners extending through a bore hole and mating bore hole. A single first one of the bore holes or mating bore holes has a first maximum radial gap and a first maximum tangential gap relative to the mechanical fastener extending through the first one of the bore holes or mating bore holes. A second one of the bore holes or mating bore holes has a second maximum radial gap and a second maximum tangential gap relative to the mechanical fastener extending through the second one of the bore holes or mating bore holes. The second maximum radial gap is greater than the first maximum radial gap or the second maximum tangential gap is greater than the first maximum tangential gap. A plurality of third ones of the bore holes or mating bore holes each have a third maximum radial gap and a third maximum tangential gap relative to the mechanical fastener extending through the third ones of the bore holes or mating bore holes. Each third maximum radial gap is greater than the first maximum radial gap and each third maximum tangential gap is greater than the first maximum tangential gap.
These and other features, aspects and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.